No cache is worth to risc your health!
My grandfather once told me the story about a Tyrolean alpinist.

This was on visit at his buddy on the Dagmar Åen, to set off for their South-Pole-expedition. But before that, he wanted to climb the highest mountain of Flensburg : the legendary "Monte Campo". The base camp was set up here and he calculated the route...

What to do? At the starting coordinates you'll find his notes in the date-format: IV.IX.MXXI
The first ascent took place at north 54° 46.[V] [X] [V+V+I] east 009° 27.[M] [V+V+I] [I].
You might want to check your maths with this ?